Traditional laminate and parquet floors are usually laid in a floating manner, i.e. without glue, on an existing subfloor which does not have to be quite smooth or plane. Any irregularities are eliminated by means of underlay material in the form of e.g. cardboard, cork or foam plastic which is laid between the floorboards and the subfloor. Floating floors of this kind are usually joined by means of glued tongue-and-groove joints, (i.e. joints with a tongue on one floorboard and a tongue groove on an adjoining floorboard) on long side and short side. In laying, the boards are joined horizontally, a projecting tongue along the joint edge of one board being inserted into a tongue groove along the joint edge of an adjoining board. The same method is used on long side as well as short side, and the boards are usually laid in parallel both long side against long side and short side against short side.
In addition to such traditional floors which are joined by means of glued tongue/tongue groove joints, floorboards have been developed in recent years, which do not require the use of glue but which are instead joined mechanically by means of so-called mechanical joint systems. These systems comprise locking means which lock the boards horizontally and vertically. The mechanical joint systems can be formed by machining the core of the board. Alternatively, parts of the locking system can be made of a separate material which is integrated with the floorboard, i.e. already joined with a floorboard in connection with the manufacture thereof at the factory. The floorboards are joined, i.e. interconnected or locked together, by various combinations of angling, snapping-in and insertion along the joint edge in the locked position. By interconnection is here meant that floorboards with connecting means are mechanically interconnected in one direction, for instance horizontally or vertically. By locking-together, however, is meant that the floorboards are locked both in the horizontal and in the vertical direction.
The principal advantages of floating floors with mechanical joint systems are that they can be laid quickly and easily by different combinations of inward angling and snapping-in. They can also easily be taken up again and be reused in some other place.